The present invention relates to conductive microparticles, their formation, and their use in a matrix of electrically nonconductive materials to produce an electrically conductive composite.
It is known that the inclusion of conductive metal particles in a matrix of electrically nonconductive material will produce a composite which is electrically conductive. Such composites rely upon particle-to-particle contact to produce a network of particles through which electrical current may flow. Typical composites rely upon particles of metals such as copper, tin, silver, gold, platinum, stainless steel, nickel, and various alloys thereof, or other conductive materials such as carbon or carbon fibers. These conductive particles have been mixed into polymers such as acrylics, phenolics, alkyds, rubbers, silicones, vinyls, urethanes, and other electrically nonconductive materials.
These composites all suffer from the following detrimental characteristics: (1) In materials utilizing metals as the conductive component, the metal particles are very dense compared to the polymer matrix and thus tend to separate from one another both before and during usage. (2) In materials utilizing carbon as the conductive component, the amount of carbon required to produce desirable conductivity causes the resulting composite to lose desirable mechanical properties. (3) In compositions which do achieve good conductivity the quantity of particles that must be incorporated make them very heavy.